Plating apparatus for plating semiconductor wafer and plating method

ABSTRACT

A plating apparatus includes a workpiece holder, a plating bath, and a clamp ring. The plating bath is underneath the workpiece holder. The clamp ring is connected to the workpiece holder. The clamp ring includes channels communicating an inner surface of the clamp ring and an outer surface of the clamp ring.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of and claims thepriority benefit of a prior application Ser. No. 17/137,267, filed onDec. 29, 2020. The entirety of the above-mentioned patent application ishereby incorporated by reference herein and made a part of thisspecification.

BACKGROUND

In the production of advanced semiconductor integrated circuits (ICs),electroplated copper is currently used because copper has a lowerelectrical resistivity and a higher current carrying capacity. However,the copper electroplating process may produce conductive features withdefects. For example, nano-bubbles trapped in the electroplated copperlayer will limit the quality of the conductive features and thereforereduce production yield of the IC product. Accordingly, formingdefect-free conductive features is one of the ongoing efforts in orderto improve electrical performance of IC devices.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1A to FIG. 1D are schematic cross-sectional views illustratingvarious stages of forming a conductive feature of a semiconductorstructure in accordance with some embodiments of the disclosure.

FIG. 2 is a schematic cross-sectional view illustrating a platingapparatus in accordance with some embodiments of the disclosure.

FIG. 3 is a flowchart illustrating a plating process of a semiconductorworkpiece in accordance with some embodiments of the disclosure.

FIG. 4A is a schematic bottom view of the semiconductor workpiece andthe clamp ring in FIG. 2 .

FIG. 4B is a schematic cross-sectional view of the workpiece holder, thesemiconductor workpiece, and the clamp ring in FIG. 2 .

FIG. 4C is a partial side view of the clamp ring in FIG. 2 .

FIG. 5A is a schematic cross-sectional view of a workpiece holder, asemiconductor workpiece, and a clamp ring in accordance with somealternative embodiments of the disclosure.

FIG. 5B is a partial side view of the clamp ring in accordance with somealternative embodiments of the disclosure.

FIG. 6 is a schematic bottom view of a semiconductor workpiece and aclamp ring in accordance with some alternative embodiments of thedisclosure.

FIG. 7 is a schematic bottom view of a semiconductor workpiece and aclamp ring in accordance with some alternative embodiments of thedisclosure.

FIG. 8 is a schematic bottom view of a semiconductor workpiece and aclamp ring in accordance with some alternative embodiments of thedisclosure.

FIG. 9A is a schematic bottom view of a semiconductor workpiece and aclamp ring in accordance with some alternative embodiments of thedisclosure.

FIG. 9B is a partial perspective view of the semiconductor workpiece andthe clamp ring in accordance with some alternative embodiments of thedisclosure.

FIG. 9C is a partial side view of the clamp ring in accordance with somealternative embodiments of the disclosure.

FIG. 10 is a schematic bottom view of a semiconductor workpiece and aclamp ring in accordance with some alternative embodiments of thedisclosure.

FIG. 11 is a schematic bottom view of a semiconductor workpiece and aclamp ring in accordance with some alternative embodiments of thedisclosure.

FIG. 12 is a schematic bottom view of a semiconductor workpiece and aclamp ring in accordance with some alternative embodiments of thedisclosure.

FIG. 13A is a schematic bottom view of a semiconductor workpiece and aclamp ring in accordance with some alternative embodiments of thedisclosure.

FIG. 13B is a partial side view of the clamp ring in accordance withsome alternative embodiments of the disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

FIG. 1A to FIG. 1D are schematic cross-sectional views illustratingvarious stages of forming a conductive feature 12 on a semiconductorstructure 10 in accordance with some embodiments of the disclosure.Referring to FIG. 1A, a base layer 11 of a semiconductor structure 10 isprovided with an opening OP. Moreover, a seed material layer 121 isformed on the base layer 11 in a conformal manner. In some embodiments,the base layer 11 is a semiconductor wafer (e.g., silicon wafer) or ispart of a semiconductor wafer. For example, the base layer 11 includes asemiconductor substrate, such as a bulk semiconductor or the like, whichmay be doped or undoped. Under this scenario, the subsequently formedconductive feature 12 (shown in FIG. 1D) may act as a through substratevia (TSV) in the semiconductor structure 10. However, the disclosure isnot limited thereto. In some alternative embodiments, the base layer 11is a dielectric layer formed over a semiconductor substrate. Under thisscenario, the conductive feature 12 (shown in FIG. 1D) may be formed asa part of interconnect circuitry in the semiconductor structure 10.

In some embodiments, the opening OP is formed by acceptable removaltechniques (e.g., lithography and etching, drilling, and/or the like).The depth of the opening OP may range from about 1 μm to about 100 μm.Although the opening OP is illustrated as not penetrating through thebase layer 11 in FIG. 1A, the disclosure is not limited thereto. In somealternative embodiments, the opening OP may penetrate through the baselayer 11 to expose element(s) underneath the base layer 11. It should benoted that the cross-sectional shape of the opening OP in FIG. 1A ismerely an example, and a dual damascene opening including a via holeconnecting a trench may be formed in the base layer 11 according to somealternative embodiments.

In some embodiments, a material of the seed material layer 121 includesCu, Ni, Co, Ru, a combination thereof, etc. For example, the seedmaterial layer 121 may include the same conductive material (e.g., Cu)as that used in the subsequent plating process. In some embodiments, theopening OP is initially lined with a barrier liner (not shown), and thenthe seed material layer 121 is deposited on the barrier liner. Thebarrier liner may bond the conductive material to the base layer 11(e.g., the dielectric layer) or may prevent interaction between theconductive material and the base layer 11 (e.g., silicon substrate). Insome embodiments, a material of the barrier liner includes Ta, TaN, Ti,TiN, or a combination thereof.

Referring to FIG. 1B, a pre-wetting process 20 is performed on thesemiconductor structure 10. For example, the seed material layer 121 istreated with the pre-wetting process 20 to increase wetting ability. Thewettability of the seed material layer 121 may be critical for thesubsequent plating process. If the seed material layer 121 cannot wetthe plating fluid, no plated material can be deposited on that area ofthe seed material layer 121, thereby forming defects. The pre-wettingprocess 20 may involve wetting the semiconductor structure 10 withfluids.

Referring to FIG. 1C, a conductive material layer 122 is formed on theseed material layer 121 through a plating process 30. The conductivematerial layer 122 may be a metallic material including a metal or ametal alloy such as copper, silver, gold, tungsten, cobalt, aluminum, oralloys thereof. In some embodiments, the plating process 30 includeselectrochemical plating (ECP) or the like. For example, after thepre-wetting process 20, ECP is performed to fill the opening OP with theconductive material layer 122. In some cases, undesirable air bubblesmay generate during the plating process 30. These air bubbles may belocated in the opening OP to create blocking spots and inhibit theconductive material layer 122 from forming on these blocking spots. Aplating apparatus 40 (shown in FIG. 4 ) and the plating process 30(shown in FIG. 3 ) which may remove the air bubbles will be describedlater.

Referring to FIG. 1D, the excess material of the conductive materiallayer 122 and the seed material layer 121 formed over a major surface 11a of the base layer 11 is removed to form the semiconductor structure 10having the conductive feature 12 embedded in the base layer 11. Forexample, the remaining seed material layer 121 and the remainingconductive material layer 122 are collectively referred to as theconductive feature 12. In some embodiments, a planarization (e.g.,chemical mechanical polishing, etching, grinding, a combination thereof,etc.) is performed to remove the excess material. In some embodiments,after the planarization, surfaces of the conductive material layer 122and the seed material layer 121 form a major surface 12 a of theconductive feature 12. As illustrated in FIG. 1D, the major surface 12 aof the conductive feature 12 is substantially level with the majorsurface 11 a of the base layer 11. In some embodiments, the barrierliner formed between the base layer 11 and the seed material layer 121is also removed by the planarization.

FIG. 2 is a schematic cross-sectional view illustrating a platingapparatus 40 in accordance with some embodiments of the disclosure.Referring to FIG. 2 , the plating apparatus 40 includes a tiltingmechanism 410, a connector 420, a rotating mechanism 430, a workpieceholder 440, a clamp ring 450, and a plating bath 460. In someembodiments, the tilting mechanism 410 includes a robotic arm, a gear, acontroller, or a combination thereof. In some embodiments, the tiltingmechanism 410 is configured to tilt a semiconductor workpiece W duringthe plating process 30. In some embodiments, the rotating mechanism 430includes a motor, a shaft, a controller, or a combination thereof. Insome embodiments, the rotating mechanism 430 is configured to rotate orspin the semiconductor workpiece W during the plating process 30.

As illustrated in FIG. 2 , the connector 420 physically connects thetilting mechanism 410 and the rotating mechanism 430. That is, thetilting mechanism 410 is connected to the rotating mechanism 430 throughthe connector 420. The connector 420 may be any connecting mechanismthat is able to physically connect the tilting mechanism 410 and therotating mechanism 430. For example, the connector 420 may be a metalblock, a plastic block, or the like that is able to lift the rotatingmechanism 430, the workpiece holder 440, and the clamp ring 450.

In some embodiments, the workpiece holder 440 is connected to therotating mechanism 430 and the clamp ring 450 is connected to theworkpiece holder 440. For example, the rotating mechanism 430 is able todrive the movement of the workpiece holder 440 and the clamp ring 450together. In some embodiments, the clamp ring 450 is engaged to theworkpiece holder 440. For example, the clamp ring 450 is detachable fromthe workpiece holder 440. In some embodiments, the workpiece holder 440includes a metal block or the like that is able to provide support forthe clamp ring 450 and the semiconductor workpiece W during the platingprocess 30. In some embodiments, the clamp ring 450 is made of inertmaterials. For example, the clamp ring 450 is made of ceramics,polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene difluoride(PVDF), fiber reinforced plastics, stainless steel,polytetrafluoroethene (PTFE), or the like. The detailed configuration ofthe clamp ring 450 will be described below.

The plating bath 460 is located underneath the workpiece holder 440 andthe clamp ring 450. In some embodiments, the plating bath 460 is filledwith a plating solution PS. In some embodiments, the plating solution PSis referred to as electrolyte. As illustrated in FIG. 2 , thesemiconductor workpiece W is fixed onto the workpiece holder 440 throughthe clamp ring 450. In some embodiments, the semiconductor workpiece Wis the semiconductor structure 10 in FIG. 1B. That is, the semiconductorworkpiece W may be a semiconductor wafer. As such, in some embodiments,the workpiece holder 440 is referred to as a wafer holder. In someembodiments, the semiconductor workpiece W is placed in a face downmanner. That is, a surface of the semiconductor workpiece W that is tobe plated faces the plating bath 460 and the plating solution PS. Forexample, as illustrated in FIG. 2 , the seed material layer 121 facesthe plating bath 460 and the plating solution PS. The plating method 30will be described below in conjunction with FIG. 2 and FIG. 3 .

FIG. 3 is a flowchart illustrating a plating process 30 of asemiconductor workpiece W in accordance with some embodiments of thedisclosure. Referring to FIG. 2 and FIG. 3 , in step S1, thesemiconductor workpiece W is placed on the workpiece holder 440 of theplating apparatus 40. Thereafter, in step S2, the semiconductorworkpiece W is fixed to the workpiece holder 440 by the clamp ring 450.In some embodiments, a portion of the clamp ring 450 is pressed againsta portion of the semiconductor workpiece W such that the semiconductorworkpiece W is securely fixed onto the workpiece holder 440.

In step S3, the semiconductor workpiece W is tilted to a first angle. Insome embodiments, the tilting of the semiconductor workpiece W may beachieved by the tilting mechanism 410. For example, since the clamp ring450, the workpiece holder 440, the rotating mechanism 430, and theconnector 420 are connected to the tilting mechanism 410, the tiltingmechanism 410 may drive the clamp ring 450, the workpiece holder 440,the rotating mechanism 430 and the connector 420 to tilt to the firstangle, thereby allowing the semiconductor workpiece W that is clamped tothe workpiece holder 440 to tilt to the first angle. In someembodiments, the first angle is about 3° with respect to a fluid levelof the plating solution PS. In some embodiments, after the semiconductorworkpiece W is tilted, the rotating mechanism 430 is utilized torotate/spin the semiconductor workpiece W. In some embodiments, aspinning speed of the semiconductor workpiece W ranges from about 10 rpm(revolutions per minute) to about 120 rpm in step S3.

Subsequently, in step S4, the semiconductor workpiece W is immersed intothe plating solution PS within the plating bath 460. For example, thetilting mechanism 410 lowers the connector 420, the rotating mechanism430, the workpiece holder 440, the clamp ring 450, and the semiconductorworkpiece W such that the semiconductor workpiece W, the workpieceholder 440, and the clamp ring 450 are immersed into the platingsolution PS. In some embodiments, the semiconductor workpiece W entersthe plating solution PS in a tilting manner. That is, the semiconductorworkpiece W is kept to be tilted with the first angle while entering theplating solution PS. In some embodiments, when clamping thesemiconductor workpiece W onto the workpiece holder 440 in step S2, airbubbles may generate on a surface of the semiconductor workpiece W dueto the clamping pressure. However, by using angled immersion in step S4,air bubbles on the surface of the semiconductor workpiece W are pushedby the wave advancing from the leading immersion edge toward thetrailing immersion edge. As such, the tilted semiconductor workpiece Wallows some of the air bubbles to discharge to the atmosphere. After thesemiconductor workpiece W is immersed into the plating solution PS, thesemiconductor workpiece W is tilted to a second angle. In someembodiments, the second angle is about 0° with respect to the fluidlevel of the plating solution PS. For example, after the semiconductorworkpiece W is immersed into the plating solution PS, the semiconductorworkpiece W is tilted back to extend horizontally.

In step S5, the semiconductor workpiece W is plated. In someembodiments, the semiconductor workpiece W is plated byelectrodeposition of a conductive material onto the semiconductorworkpiece W. The electrodeposition occurs by positioning an anode andthe semiconductor workpiece W (the cathode) in the plating solution PSand applying a current such that metal ions in the plating solution PSis plated onto the semiconductor workpiece W. In step S5, the rotatingmechanism 430 is utilized to rotate/spin the semiconductor workpiece W.In some embodiments, a spinning speed of the semiconductor workpiece Wranges from about 30 rpm to about 200 rpm in step S5.

After the electrodeposition of the conductive material onto thesemiconductor workpiece W is completed, the plated semiconductorworkpiece W is retrieved from the plating bath 460 in step S6. Forexample, the tilting mechanism 410 pulls the semiconductor workpiece Wout of the plating solution PS. Thereafter, the rotating mechanism 430spins the semiconductor workpiece W to spin dry the semiconductorworkpiece W. That is, the plating solution PS left on the semiconductorworkpiece W is removed from the semiconductor workpiece W throughspinning the semiconductor workpiece W. In some embodiments, a spinningspeed of the semiconductor workpiece W ranges from about 250 rpm toabout 350 rpm in step S6. In some embodiments, the process in step S6 isreferred to as reclaim spin.

In step S7, the plated semiconductor workpiece W is rinsed. In someembodiments, the plated semiconductor workpiece W is rinsed by jettingthe plated surface of the semiconductor workpiece W with distill water,so as to remove the plating solution PS left on the plated surface ofthe semiconductor workpiece W. In some embodiments, during step S7, therotating mechanism 430 also spins the semiconductor workpiece W. In someembodiments, a spinning speed of the semiconductor workpiece W rangesfrom about 450 rpm to about 550 rpm in step S7. Thereafter, in step S8,the plated semiconductor workpiece W is dried. In some embodiments, theplated semiconductor workpiece W is dried through spin dry. In someembodiments, a spinning speed of the semiconductor workpiece W rangesfrom about 700 rpm to about 800 rpm in step S8. In step S9, after theplated semiconductor workpiece W is dried, the plated semiconductorworkpiece W is removed from the plating apparatus 40, so as to completethe plating process 30.

As mentioned above, by immersing the semiconductor workpiece W into theplating solution PS in a tilting manner, some of the air bubblesgenerated may be discharged. However, depending on the number of airbubbles generated, the angled immersion in step S4 may not be sufficientto remove all of the air bubbles. Moreover, during the immersion of thesemiconductor workpiece W into the plating solution PS, additional airbubbles may be generated on the surface of the semiconductor workpieceW. The air bubbles on the surface of the semiconductor workpiece W wouldcreate blocking spots and inhibits the conductive material from formingon these blocking spots. Therefore, it is crucial to remove the airbubbles on the surface of the semiconductor workpiece W before theconductive material is plated onto the semiconductor workpiece W. Insome embodiments, by forming channels in the clamp ring 450, the airbubbles may be sufficiently removed through these channels by spinningthe semiconductor workpiece W before the semiconductor workpiece W isplated. Various configurations of the clamp ring 450 having channelswill be described below.

FIG. 4A is a schematic bottom view of the semiconductor workpiece W andthe clamp ring 450 in FIG. 2 . FIG. 4B is a schematic cross-sectionalview of the workpiece holder 440, the semiconductor workpiece W, and theclamp ring 450 in FIG. 2 . FIG. 4C is a partial side view of the clampring 450 in FIG. 2 . Referring to FIG. 4A to FIG. 4C, the clamp ring 450is connected to the workpiece holder 440. On the other hand, thesemiconductor workpiece W is placed over the workpiece holder 440 and isclamped to the workpiece holder 440 by the clamp ring 450. In someembodiments, the clamp ring 450 is engaged to the workpiece holder 440and is detachable from the workpiece holder 440.

As illustrated in FIG. 4A and FIG. 4B, the clamp ring 450 includes abody portion 452, a protruding portion 454, and channels 456. In someembodiments, the body portion 452 is engaged/connected to the workpieceholder 440. In some embodiments, the body portion 452 has an innersurface IS1 and an outer surface OS1 opposite to the inner surface IS1.In some embodiments, the inner surface IS1 of the body portion 452 isparallel to the outer surface OS1 of the body portion 452. Asillustrated in FIG. 4B, the outer surface OS1 of the body portion 452 isaligned with a lateral surface LS₄₄₀ of the workpiece holder 440. On theother hand, the inner surface IS1 of the body portion 452 is coplanarwith a lateral surface LS_(W) of the semiconductor workpiece W. That is,the body portion 452 covers the lateral surface LS_(W) of thesemiconductor workpiece W. In some embodiments, a bottom surface B S452of the body portion 452 is substantially coplanar with a bottom surfaceBS_(W) of the semiconductor workpiece W. In some embodiments, the bodyportion 452 has a rectangular cross-sectional view, as shown in FIG. 4B.

In some embodiments, the protruding portion 454 of the clamp ring 450 isconnected to the body portion 452 of the clamp ring 450. For example,the protruding portion 454 protrudes from the bottom surface BS₄₅₂ ofthe body portion 452. In some embodiments, the protruding portion 454and the body portion 452 of the clamp ring 450 are integrally formed.For example, the protruding portion 454 and the body portion 452 aremade of a same material. In some embodiments, the protruding portion 454has an inner surface IS2 and an outer surface OS2. In some embodiments,the inner surface IS2 of the protruding portion 454 is not parallel tothe outer surface OS2 of the protruding portion 454. In someembodiments, the inner surface IS2 of the protruding portion 454 is aninclined surface. That is, the protruding portion 454 has an inclinedinner surface IS2. In some embodiments, the inclined inner surface IS2of the protruding portion 454 is connected to the outer surface OS2 ofthe protruding portion 454. In some embodiments, the protruding portion454 further has a top surface TS454 which connects the outer surface OS2and the inclined inner surface IS2. In some embodiments, the protrudingportion 454 has a triangular cross-sectional view, as shown in FIG. 4B.In some embodiments, the top surface TS₄₅₄ of the protruding portion 454is coplanar with the bottom surface BS₄₅₂ of the body portion 452 andthe bottom surface BS_(W) of the semiconductor workpiece W. That is, aportion of the protruding portion 454 extends horizontally to cover aportion of the bottom surface BS_(W) of the semiconductor workpiece W.In some embodiments, the outer surface OS2 of the protruding portion 454is aligned with the outer surface OS1 of the body portion 452. In someembodiments, the protruding portion 454 is a continuous pattern. Forexample, as illustrated in the bottom view of FIG. 4A, the protrudingportion 454 is a continuous ring.

In some embodiments, the inner surface IS1 of the body portion 452 andthe inner surface IS2 of the protruding portion 454 are collectivelyreferred to as an inner surface IS of the clamp ring 450. Similarly, theouter surface OS1 of the body portion 452 and the outer surface OS2 ofthe protruding portion 454 are collectively referred to as an outersurface OS of the clamp ring 450. As illustrated in FIG. 4A and FIG. 4B,the channels 456 penetrate through the clamp ring 450 to communicate theinner surface IS and the outer surface OS of the clamp ring 450. Sincethe channels 456 communicate the inner surface IS and the outer surfaceOS of the clamp ring 450, the channels 456 may serve as dischargingmechanisms for the air bubbles trapped on the bottom surface BS_(W) ofthe semiconductor workpiece W during the plating process 30. Forexample, the air bubbles are removed through the channels 456 of theclamp ring 450 by spinning the semiconductor workpiece W before thesemiconductor workpiece W is plated (i.e. between step S4 and step S5 inFIG. 3 ). In some embodiments, the undesired air bubbles on the bottomsurface BS_(W) of the semiconductor workpiece W can be expelled throughthe channels 456 of the clamp ring 450 by the forced centrifugaldirection flow, which is generated by the pressure difference betweenthe inner surface IS and the outer surface OS of the clamp ring 450 whenthe semiconductor workpiece W is spinning in the plating bath 460according to Bernoulli's principle. For example, since the velocity atthe inner surface IS is smaller than the velocity at the outer surfaceOS, the pressure at the inner surface IS is larger than the pressure atthe outer surface OS. The larger pressure at the inner surface IS wouldpush the air bubbles to the outer surface with lower pressure, and thechannels 456 provide paths for the air bubbles to travel from the innersurface IS to the outer surface OS of the clamp ring 450. As such, theundesired air bubbles may be expelled from the semiconductor workpieceW, and the plating quality may be sufficiently enhanced. In someembodiments, since the channels 456 provide the paths for air to travel,the channels 456 are referred to as vents.

In some embodiments, the channels 456 penetrate through the protrudingportion 454 of the clamp ring 450 to communicate the inner surface IS2and the outer surface OS2 of the protruding portion 454. As illustratedin FIG. 4B, since the channels 456 are located within the protrudingportion 454 of the clamp ring 450, the channels 456 (i.e. the vents) arealso located below the bottom surface BS_(W) of the semiconductorworkpiece W. As illustrated in FIG. 4A and FIG. 4B, each channel 456 hasa first end located at the inner surface IS of the clamp ring 450 and asecond end located at the outer surface OS of the clamp ring 450. Insome embodiments, the first end is referred to as an inlet IL and thesecond end is referred as an outlet OL. For example, each vent has aninlet IL and an outlet OL. In some embodiments, the inlets IL of thechannels 456 (i.e. the vents) are located on the inclined inner surfaceIS2 of the protruding portion 454 while the outlets OL of the channels456 (i.e. the vents) are located on the outer surface OS2 of theprotruding portion 454. Moreover, the inlets IL are closer to thesemiconductor workpiece W than the outlets OL.

As illustrated in FIG. 4A to FIG. 4C, the channels 456 are circularchannels. That is, the inlets IL and the outlets OL of the channel 456are circular openings. However, the disclosure is not limited thereto.In some alternative embodiments, the channels 456 may be rectangularchannels, triangular channels, or may have other geometries. In someembodiments, a size of the first end (i.e. the inlet IL) of the channel456 is substantially equal to a size of the second end (i.e. the outletOL) of the channel 456. For example, a radius R1 of the inlet IL of thechannel 456 is substantially equal to a radius R2 of the outlet OL ofthe channel 456. In some embodiments, the radius R1 and the radius R2range from about 3 μm to about 10 μm. In some embodiments, a distance dbetween two adjacent channels 456 ranges from about 5 μm to about 10 μm.As illustrated in FIG. 4A, each channel 456 is curved along acounterclockwise direction from the bottom view. In some embodiments,when the semiconductor workpiece W is spun along the counterclockwisedirection, the arrangement of the channels 456 may further aid the airbubbles to travel from the inner surface IS to the outer surface OS ofthe clamp ring 450 rapidly.

FIG. 5A is a schematic cross-sectional view of a workpiece holder 440, asemiconductor workpiece W, and a clamp ring 450 a in accordance withsome alternative embodiments of the disclosure. FIG. 5B is a partialside view of the clamp ring 450 a in accordance with some alternativeembodiments of the disclosure. Referring to FIG. 5A and FIG. 5B, theworkpiece holder 440, the semiconductor workpiece W, and the clamp ring450 a in FIG. 5A and FIG. 5B are respectively similar to the workpieceholder 440, the semiconductor workpiece W, and the clamp ring 450 inFIG. 4A to FIG. 4C, so similar elements are denoted by the samereference numeral and the detailed descriptions thereof are omittedherein. However, in the clamp ring 450 a of FIG. 5A and FIG. 5B,multiple rows of channels 456 are provided in the protruding portion454. For example, as illustrated in FIG. 5B, multiple channels 456 arealigned along a vertical (i.e. z-axis) direction. That is, each channel456 is aligned with a corresponding channel 456 in the adjacent row. Insome embodiments, each channel 456 is parallel with another channel 456that is located directly above or directly underneath it.

FIG. 6 is a schematic bottom view of a semiconductor workpiece W and aclamp ring 450 b in accordance with some alternative embodiments of thedisclosure. Referring to FIG. 6 , the semiconductor workpiece W and theclamp ring 450 b in FIG. 6 are respectively similar to the semiconductorworkpiece W and the clamp ring 450 in FIG. 4A to FIG. 4C, so similarelements are denoted by the same reference numeral and the detaileddescriptions thereof are omitted herein. However, in the clamp ring 450b of FIG. 6 , a size of the first end (i.e. the inlet IL) of the channel456 is different from a size of the second end (i.e. the outlet OL) ofthe channel 456. In some embodiments, a radius R1 of the inlet IL of thechannel 456 is smaller than a radius R2 of the outlet OL of the channel456. For example, the size of each channel 456 gradually increases fromthe inner surface IS of the clamp ring 450 b toward the outer surface OSof the clamp ring 450 b. In some embodiments, each channel 456 is a hornshape. In some embodiments, the radius R1 ranges from about 3 μm toabout 7 μm and the radius R2 ranges from about 8 μm to about 15 μm.

FIG. 7 is a schematic bottom view of a semiconductor workpiece W and aclamp ring 750 c in accordance with some alternative embodiments of thedisclosure. Referring to FIG. 7 , the semiconductor workpiece W and theclamp ring 450 c in FIG. 7 are respectively similar to the semiconductorworkpiece W and the clamp ring 450 in FIG. 4A to FIG. 4C, so similarelements are denoted by the same reference numeral and the detaileddescriptions thereof are omitted herein. However, in the clamp ring 450c of FIG. 7 , a size of the first end (i.e. the inlet IL) of the channel456 is different from a size of the second end (i.e. the outlet OL) ofthe channel 456. In some embodiments, a radius R1 of the inlet IL of thechannel 456 is larger than a radius R2 of the outlet OL of the channel456. For example, the size of each channel 456 gradually decreases fromthe inner surface IS of the clamp ring 450 c toward the outer surface OSof the clamp ring 450 c. In some embodiments, each channel 456 is a hornshape. In some embodiments, the radius R1 ranges from about 8 μm toabout 15 μm and the radius R2 ranges from about 3 μm to about 7 μm.

FIG. 8 is a schematic bottom view of a semiconductor workpiece W and aclamp ring 450 d in accordance with some alternative embodiments of thedisclosure. Referring to FIG. 8 , the semiconductor workpiece W and theclamp ring 450 d in FIG. 8 are respectively similar to the semiconductorworkpiece W and the clamp ring 450 in FIG. 4A to FIG. 4C, so similarelements are denoted by the same reference numeral and the detaileddescriptions thereof are omitted herein. However, in the clamp ring 450d of FIG. 8 , each channel 456 is curved along a clockwise directionfrom the bottom view. In some embodiments, when the semiconductorworkpiece W is spun along the clockwise direction, the arrangement ofthe channels 456 may further aid the air bubbles to travel from theinner surface IS to the outer surface OS of the clamp ring 450 drapidly.

FIG. 9A is a schematic bottom view of a semiconductor workpiece W and aclamp ring 450 e in accordance with some alternative embodiments of thedisclosure. FIG. 9B is a partial perspective view of the semiconductorworkpiece W and the clamp ring 450 e in accordance with some alternativeembodiments of the disclosure. FIG. 9C is a partial side view of theclamp ring 450 e in accordance with some alternative embodiments of thedisclosure. For simplicity in visualization, orientations of thesemiconductor workpiece W and the clamp ring 450 e in FIG. 9B areflipped as compared to FIG. 9A and FIG. 9C. Referring to FIG. 9A to FIG.9C, the semiconductor workpiece W and the clamp ring 450 e in FIG. 9A toFIG. 9C are respectively similar to the semiconductor workpiece W andthe clamp ring 450 in FIG. 4A to FIG. 4C, so similar elements aredenoted by the same reference numeral and the detailed descriptionsthereof are omitted herein. However, the channels 456 in the clamp ring450 of FIG. 4A to FIG. 4C are omitted in the clamp ring 450 e of FIG. 9Ato FIG. 9C. In some embodiments, the clamp ring 450 e includes a bodyportion 454, a protruding portion 545, and channels 458. The bodyportion 452 of the clamp ring 450 e in FIG. 9A to FIG. 9C is similar tothe body portion 452 in FIG. 4A to FIG. 4C, so the detailed descriptionthereof is omitted herein.

In some embodiments, the protruding portion 454 of the clamp ring 450 ein FIG. 9A to FIG. 9C is similar to the protruding portion 454 of theclamp ring 450 in FIG. 4A to FIG. 4C. However, the protruding portion454 of the clamp ring 450 e is not a continuous pattern. For example,the protruding portion 454 of the clamp ring 450 e includes a pluralityof protruding patterns 454 a disconnected from one another. That is, theprotruding patterns 454 a are spatially separated from one another. Insome embodiments, the protruding portion 454 of the clamp ring 450 e isconnected to the body portion 452 of the clamp ring 450 e. For example,the protruding patterns 454 a of the protruding portion 454 protrudefrom the bottom surface BS₄₅₂ of the body portion 452. In someembodiments, the protruding patterns 454 a and the body portion 452 ofthe clamp ring 450 e are integrally formed. However, the disclosure isnot limited thereto. In some alternative embodiments, the protrudingpatterns 454 a may be installed on the body portion 452 and may bedetachable from the body portion 452. A material of the protrudingpatterns 454 a may be the same as or different from the material of thebody portion 452. In some embodiments, each protruding pattern 454 a hasan inner surface IS2 and an outer surface OS2. In some embodiments, theinner surface IS2 of the protruding pattern 454 a is not parallel to theouter surface OS2 of the protruding pattern 454 a. In some embodiments,the inner surface IS2 of the protruding pattern 454 a is an inclinedsurface. That is, the protruding pattern 454 a has an inclined innersurface IS2. In some embodiments, the inclined inner surface IS2 of theprotruding pattern 454 a is connected to the outer surface OS2 of theprotruding pattern 454 a. In some embodiments, each of the protrudingpatterns 454 a is a triangular prism, as shown in FIG. 9B. In someembodiments, a portion of each protruding pattern 454 a extendshorizontally to cover a portion of the bottom surface BS_(W) of thesemiconductor workpiece W. In some embodiments, the outer surface OS2 ofthe protruding pattern 454 a is aligned with the outer surface OS1 ofthe body portion 452.

In some embodiments, the inner surface IS1 of the body portion 452 andthe inner surfaces IS2 of the protruding patterns 454 a (i.e. theprotruding portion 454) are collectively referred to as an inner surfaceIS of the clamp ring 450 e. Similarly, the outer surface OS1 of the bodyportion 452 and the outer surface OS2 of protruding patterns 454 a (i.e.the protruding portion 454) are collectively referred to as an outersurface OS of the clamp ring 450 e. As illustrated in FIG. 9A and FIG.9B, each channel 458 is located between two adjacent protruding patterns454 a to communicate the inner surface IS and the outer surface OS ofthe clamp ring 450 e. For example, each channel 458 is defined by aspace between two adjacent protruding patterns 454 a. Since the channels458 communicate the inner surface IS and the outer surface OS of theclamp ring 450 e, the channels 458 may serve as discharging mechanismsfor the air bubbles trapped on the bottom surface BS_(W) of thesemiconductor workpiece W during the plating process 30. For example,the air bubbles are removed through the channels 458 of the clamp ring450 e by spinning the semiconductor workpiece W before the semiconductorworkpiece W is plated. In some embodiments, the undesired air bubbles onthe bottom surface BS_(W) of the semiconductor workpiece W can beexpelled through the channels 458 of the clamp ring 450 e by the forcedcentrifugal direction flow when the semiconductor workpiece W isspinning in the plating bath 460. As such, the plating quality may besufficiently enhanced. In some embodiments, since the channels 458provide the paths for air to travel, the channels 458 are referred to asvents.

As illustrated in FIG. 9B and FIG. 9C, since the channels 458 arelocated between two adjacent protruding patterns 454 a of the clamp ring450 e, the channels 458 (i.e. the vents) are also located below thebottom surface BS_(W) of the semiconductor workpiece W. As illustratedin FIG. 9A, each channel 458 has a first end located at a same plane asthe inner surface IS of the clamp ring 450 e and a second end located ata same plane as the outer surface OS of the clamp ring 450 e. In someembodiments, the first end is referred to as an inlet IL and the secondend is referred as an outlet OL. For example, each vent has an inlet ILand an outlet OL. In some embodiments, the inlets IL of the channels 458(i.e. the vents) are located at a same plane as the inclined innersurfaces IS2 of the protruding patterns 454 a while the outlets OL ofthe channels 458 (i.e. the vents) are located at a same plane as theouter surfaces OS2 of the protruding patterns 454 a. Moreover, theinlets IL are closer to the semiconductor workpiece W than the outletsOL.

As illustrated in FIG. 9A to FIG. 9C, the channels 458 are openchannels. In some embodiments, a size of the each channel 458 issubstantially equal to a distance between two adjacent protrudingpatterns 454 a. In some embodiments, a size of the first end (i.e. theinlet IL) of the channel 458 is substantially equal to a size of thesecond end (i.e. the outlet OL) of the channel 458. For example, a widthw1 of the inlet IL of the channel 458 is substantially equal to a widthw2 of the outlet OL of the channel 458. In some embodiments, the widthw1 and the width w2 range from about 5 μm to about 15 μm. In someembodiments, a width w3 of each protruding pattern 454 a is not uniform.For example, the width w3 of the protruding pattern 454 a graduallyincreases or decreases from the inner surface IS2 of the protrudingpattern 454 a toward the outer surface OS2 of the protruding pattern 454a. However, the disclosure is not limited thereto. In some alternativeembodiments, the width w3 of each protruding pattern 454 a is uniform.In some embodiments, the width w3 of each protruding pattern 454 aranges from about 5 μm to about 15 μm. As illustrated in FIG. 9A, eachchannel 458 is curved along a counterclockwise direction from the bottomview. In some embodiments, when the semiconductor workpiece W is spunalong the counterclockwise direction, the arrangement of the channels458 may further aid the air bubbles to travel from the inner surface ISto the outer surface OS of the clamp ring 450 f rapidly.

FIG. 10 is a schematic bottom view of a semiconductor workpiece W and aclamp ring 450 f in accordance with some alternative embodiments of thedisclosure. Referring to FIG. 10 , the semiconductor workpiece W and theclamp ring 450 f in FIG. 10 are respectively similar to thesemiconductor workpiece W and the clamp ring 450 e in FIG. 9A to FIG.9C, so similar elements are denoted by the same reference numeral andthe detailed descriptions thereof are omitted herein. However, in theclamp ring 450 f of FIG. 10 , a size of the first end (i.e. the inletIL) of the channel 458 is different from a size of the second end (i.e.the outlet OL) of the channel 458. In some embodiments, a width w1 ofthe inlet IL of the channel 458 is smaller than a width w2 of the outletOL of the channel 458. For example, the size of each channel 458gradually increases from the inner surface IS of the clamp ring 450 ftoward the outer surface OS of the clamp ring 450 f. In someembodiments, each channel 458 is a horn shape. In some embodiments, thewidth w1 ranges from about 3 μm to about 7 μm and the width w2 rangesfrom about 8 μm to about 12 μm. In some embodiments, a width w3 of eachprotruding pattern 454 a is not uniform. For example, the width w3 ofthe protruding pattern 454 a gradually decreases from the inner surfaceIS2 of the protruding pattern 454 a toward the outer surface OS2 of theprotruding pattern 454 a. However, the disclosure is not limitedthereto. In some alternative embodiments, the width w3 of eachprotruding pattern 454 a is uniform. In some embodiments, the width w3of each protruding pattern 454 a ranges from about 5 μm to about 15 μm.

FIG. 11 is a schematic bottom view of a semiconductor workpiece W and aclamp ring 450 g in accordance with some alternative embodiments of thedisclosure. Referring to FIG. 11 , the semiconductor workpiece W and theclamp ring 450 g in FIG. 11 are respectively similar to thesemiconductor workpiece W and the clamp ring 450 e in FIG. 9A to FIG.9C, so similar elements are denoted by the same reference numeral andthe detailed descriptions thereof are omitted herein. However, in theclamp ring 450 g of FIG. 11 , a size of the first end (i.e. the inletIL) of the channel 458 is different from a size of the second end (i.e.the outlet OL) of the channel 458. In some embodiments, a width w1 ofthe inlet IL of the channel 458 is larger than a width w2 of the outletOL of the channel 458. For example, the size of each channel 458gradually decreases from the inner surface IS of the clamp ring 450 gtoward the outer surface OS of the clamp ring 450 g. In someembodiments, each channel 458 is a horn shape. In some embodiments, thewidth w1 ranges from about 8 μm to about 12 μm and the width w2 rangesfrom about 3 μm to about 7 μm. In some embodiments, a width w3 of eachprotruding pattern 454 a is not uniform. For example, the width w3 ofthe protruding pattern 454 a gradually increases from the inner surfaceIS2 of the protruding pattern 454 a toward the outer surface OS2 of theprotruding pattern 454 a. However, the disclosure is not limitedthereto. In some alternative embodiments, the width w3 of eachprotruding pattern 454 a is uniform. In some embodiments, the width w3of each protruding pattern 454 a ranges from about 5 μm to about 15 μm.

FIG. 12 is a schematic bottom view of a semiconductor workpiece W and aclamp ring 450 h in accordance with some alternative embodiments of thedisclosure. Referring to FIG. 12 , the semiconductor workpiece W and theclamp ring 450 h in FIG. 12 are respectively similar to thesemiconductor workpiece W and the clamp ring 450 e in FIG. 9A to FIG.9C, so similar elements are denoted by the same reference numeral andthe detailed descriptions thereof are omitted herein. However, in theclamp ring 450 h of FIG. 10 , each channel 458 is curved along aclockwise direction from the bottom view. In some embodiments, when thesemiconductor workpiece W is spun along the clockwise direction, thearrangement of the channels 458 may further aid the air bubbles totravel from the inner surface IS to the outer surface OS of the clampring 450 h rapidly.

FIG. 13A is a schematic bottom view of a semiconductor workpiece W and aclamp ring 450 i in accordance with some alternative embodiments of thedisclosure. FIG. 13B is a partial side view of the clamp ring 450 i inaccordance with some alternative embodiments of the disclosure.Referring to FIG. 13A and FIG. 13B, the semiconductor workpiece W andthe clamp ring 450 i in FIG. 13A and FIG. 13B are respectively similarto the semiconductor workpiece W and the clamp ring 450 e in FIG. 9A toFIG. 9C, so similar elements are denoted by the same reference numeraland the detailed descriptions thereof are omitted herein. However, theclamp ring 450 i in FIG. 13A and FIG. 13B further includes a pluralityof channels 456. In some embodiments, the channels 456 of the clamp ring450 i in FIG. 13A and FIG. 13B are similar to the channels 456 of theclamp ring 450 in FIG. 4A to FIG. 4C, so the detailed descriptionsthereof are omitted herein. As illustrated in FIG. 13B, the channels 456penetrate through the protruding patterns 454 a of the protrudingportion 454. In some embodiments, each protruding pattern 454 acorrespond to one channel 456. However, the disclosure is not limitedthereto. In some alternative embodiments, multiple channels 456 maypenetrate through a same protruding pattern 454 a. Since the channels456 and the channels 458 communicate the inner surface IS and the outersurface OS of the clamp ring 450 i, the channels 456 and the channels458 may serve as discharging mechanisms for the air bubbles trapped onthe bottom surface BS_(W) of the semiconductor workpiece W during theplating process 30. In some embodiments, the undesired air bubbles onthe bottom surface BS_(W) of the semiconductor workpiece W can beexpelled through the channels 456 and the channels 458 of the clamp ring450 i. As such, the plating quality may be sufficiently enhanced.

In accordance with some embodiments of the disclosure, a platingapparatus includes a workpiece holder, a plating bath, and a clamp ring.The plating bath is underneath the workpiece holder. The clamp ring isconnected to the workpiece holder. The clamp ring includes channelscommunicating an inner surface of the clamp ring and an outer surface ofthe clamp ring.

In accordance with some alternative embodiments of the disclosure, aplating apparatus for plating a semiconductor wafer includes a waferholder, a plating bath, and a clamp ring. The plating bath is underneaththe wafer holder. The clamp ring is connected to the wafer holder. Theclamp ring includes a body portion, a protruding portion connected tothe body portion, and vents. The protruding portion covers a portion ofa bottom surface of the semiconductor wafer and has an inclined innersurface. The vents are located below the bottom surface of thesemiconductor wafer. The vents has inlets and outlets, and the inletsare closer to the semiconductor wafer than the outlets.

In accordance with some embodiments of the disclosure, a plating methodincludes at least the following steps. A semiconductor workpiece isplaced on a workpiece holder. The semiconductor workpiece is fixed tothe workpiece holder by a clamp ring. The clamp ring is connected to theworkpiece holder. The clamp ring includes channels communicating aninner surface of the clamp ring and an outer surface of the clamp ring.The semiconductor workpiece is tilted to a first angle. Thesemiconductor workpiece is immersed into a plating solution within aplating bath and the semiconductor workpiece is tilted to a secondangle. The semiconductor workpiece is plated.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A plating apparatus, comprising: a workpieceholder; a plating bath underneath the workpiece holder; and a clamp ringconnected to the workpiece holder, wherein the clamp ring comprisesfirst vents communicating an inner surface of the clamp ring and anouter surface of the clamp ring, wherein the clamp ring comprises a bodyportion and a protruding portion protruding from a bottom surface of thebody portion, and the first vents penetrate through the protrudingportion, the protruding portion comprises a plurality of protrudingpatterns disconnected from one another, and each of the first vents isdefined by two adjacent protruding patterns and the bottom surface ofthe body portion.
 2. The plating apparatus of claim 1, wherein the clampring further comprises second vents communicating the inner surface ofthe clamp ring and the outer surface of the clamp ring, each of thesecond vents has a first end located at the inner surface of the clampring and a second end located at the outer surface of the clamp ring,and a size of the first end is substantially equal to a size of thesecond end.
 3. The plating apparatus of claim 1, wherein the clamp ringfurther comprises second vents communicating the inner surface of theclamp ring and the outer surface of the clamp ring, each of the secondvents has a first end located at the inner surface of the clamp ring anda second end located at the outer surface of the clamp ring, and a sizeof the first end is different from a size of the second end.
 4. Theplating apparatus of claim 2, wherein the second vents penetrate throughthe protruding patterns.
 5. The plating apparatus of claim 3, whereinthe second vents penetrate through the protruding patterns.
 6. Theplating apparatus of claim 2, wherein each of the second vents is curvedalong a clockwise direction or a counterclockwise direction from abottom view.
 7. The plating apparatus of claim 3, wherein each of thesecond vents is curved along a clockwise direction or a counterclockwisedirection from a bottom view.
 8. The plating apparatus of claim 1,wherein a size of a first end of each of the first vents is equal to asize of a second end each of the first vents.
 9. The plating apparatusof claim 1, wherein each of the first vents is curved along a clockwisedirection from a bottom view.
 10. The plating apparatus of claim 1,wherein each of the first vents is curved along a counterclockwisedirection from a bottom view.
 11. The plating apparatus of claim 1,further comprising: a rotating mechanism connected to the workpieceholder; a connector connected to the rotating mechanism; and a tiltingmechanism connected to the rotating mechanism through the connector. 12.A plating apparatus for plating a semiconductor wafer, comprising: awafer holder; a plating bath underneath the wafer holder; and a clampring connected to the wafer holder, wherein the clamp ring comprises abody portion, a protruding portion connected to the body portion, firstvents and second vents, the protruding portion covers a first portion ofa bottom surface of the semiconductor wafer and has an inclined innersurface, the first vents and the second vents are located below thebottom surface of the semiconductor wafer, the second vents has inletsand outlets, and the inlets are closer to the semiconductor wafer thanthe outlets, the protruding portion comprises a plurality of protrudingpatterns disconnected from one another, and two adjacent protrudingpatterns are spaced apart by each of the first vents.
 13. The platingapparatus of claim 12, wherein the inlets of the second vents arelocated on the inclined inner surface of the protruding portion.
 14. Theplating apparatus of claim 12, wherein a top surface of the protrudingportion is coplanar with the bottom surface of the semiconductor wafer.15. The plating apparatus of claim 12, wherein an outer surface of thebody portion is aligned with an outer surface of the protruding portion,the inclined inner surface of the protruding portion is connected to theouter surface of the protruding portion, and the outlets of the secondvents are located on the outer surface of the protruding portion. 16.The plating apparatus of claim 12, wherein the body portion covers alateral surface of the semiconductor wafer.
 17. A plating method,comprising: placing a semiconductor workpiece on a workpiece holder;fixing the semiconductor workpiece to the workpiece holder by a clampring, wherein the clamp ring is connected to the workpiece holder, andthe clamp ring comprise vents communicating an inner surface of theclamp ring and an outer surface of the clamp ring, wherein the clampring comprises a body portion and a protruding portion protruding from abottom surface of the body portion, and the vents penetrate through theprotruding portion, the protruding portion comprises a plurality ofprotruding patterns disconnected from one another, and each of the ventsis defined by two adjacent protruding patterns and the bottom surface ofthe body portion; tilting the semiconductor workpiece to a first angle;immersing the semiconductor workpiece into a plating solution within aplating bath and tilting the semiconductor workpiece to a second angle;and plating the semiconductor workpiece.
 18. The method of claim 17,wherein the first angle is about 3° with respect to a fluid level of theplating solution and the second angle is about 0° with respect to thefluid level of the plating solution.
 19. The method of claim 17, whereinthe semiconductor workpiece is tilted to the second angle after beingimmersed into the plating solution.
 20. The method of claim 17, whereinair bubbles are generated during the immersion of the semiconductorworkpiece into the plating solution, and the air bubbles are removedthrough the channels of the clamp ring by spinning the semiconductorworkpiece before the semiconductor workpiece is plated.